Any advice on the list would be really help full as my current army is daemonhunter ( grey knights mainly ) and I dont know much of the eldar at this time or what forms a solid list for them. Asurmen will be in the wave serpent with the dire avengers if anyone is wondering.

It's a very good first list. A few suggestions:
- I generally find the executioner to be a much better weapon to put on a banshee exarch since you'll get a few strength 5 attacks.
- War shout is unreliable seing as how Howling banshees are usually attacking MEQs which are usually ld 9 or 10 or even fearless. I would drop those two upgrades. (-10)
- Your Dire Avenger squad is dying for an exarch, You may want to drop a single pathfinder then add the exarch and bladestorm(any additional exarch upgrades you want can be added if you drop one more pathfinder).

as per hsin - executioner by far best weapon for banshee exarch as it deals with banshees chief failing - lack of strength

Other things- upgrades for serpents:
ALL serpents should take spirit stones
serpents carrying assault squads (banshees) should take vectored engines
Therefore drop the VE off the DA serpents and make sure all serpents have spirit stones

any reason why Asurmen is being taken? Sure he is the most survivable of the PL but he is the least offensive as well. I actually rank him one of the lowest along with Baharoth. If I were you I would switch him out for yriel as he still has a decent save but is absolutely amazing in CC as well. Plus, he frees up another 75 points.

The runes of warding are only good if you face alot of enemy psykers. For an all somers list, I say drop them. The runes of witnessing I have found, make it easier to suffer perils of the warp in which case you lose your seer due to insta kill. I would say drop both of these and try to squeeze the points for spirit stones and maybe an offensive power like eldritch storm. Doom + storm can be pretty sweet and storm on top of a vehicle has a chance to put the rear armour your way.